An ICN network is a conceptualization of a networking protocol stack, in particular layers 3 and above of a network protocol stack. The CCN network as well similar networks like named data networking (NDN) networks are particular architectures and implementation of an ICN network. ICN networks, CCN and NDN networks are based on the premise of naming resources in these networks. In particular, the naming relates to the use of a globally shared namespace for objects that allows entities in these networks to retrieve any content of interest. NDN networks and CCN networks have similar architectures, thus for sake of clarity examples related to CCN networks are discussed herein below.
Thus, within a CCN network a name is utilized to identify a content object instead of an Internet Protocol (IP) address of the host of the content. In an IP network, routing is based on host names (e.g., source and destination addresses). In a CCN network by contrast, routing is based on a uniform resource identifier (URI) or similar identifier for a content object. CCN routing is performed hop-by-hop, using a longest prefix matching on the CCN name. All communications seeking to access data are framed as a request and response transaction. A CCN client sends a message referred to as a CCN interest to the nodes in the CCN. The nodes of the CCN network respond with a content object identified by a CCN name in the CCN interest. These CCN content objects are returned via a CCN response.
All content object packets are cryptographically signed by their initial provider. A CCN client can thus verify the integrity and authenticity of the content even if the packet comes from untrusted links or untrusted hosts. As a direct effect, CCN nodes in the CCN network are allowed to cache packets locally in a table called the content store. When a CCN network node receives a CCN interest packet, it can check whether its local content store has the requested content object and can send it back if found. The look up in the content store is by the CCN name. If the CCN name is not found in the local content store, then the CCN interest is forwarded according to entries for the CCN name in a forwarding information base (FIB) of the CCN network node.